Molded picket fence section

ABSTRACT

A picket fence section is made as a single integral plastic component. The fence section can be made in various length including a length appropriate for securement between posts spaced at eight foot centers. The picket fence section is preferrably of a high density polyethylene material and made by blow molding.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to plastic picket fence systems andin particular, relates to a one piece picket fence section.

[0002] There are a number of fence products available where the customerpurchases a finished fence section of an appropriate length. These fencesections can be made of plastic or wood and are often factory assembled.Many of the components of the plastic fence section are extruded plasticcomponents and these components are then mechanically secured toextruded main support members.

[0003] With these products, the end user merely purchases a finishedsection. Unfortunately, these products still have a very substantialcost with respect to the assembly of the fence section and it would bedesirable to produce a lower cost competing product.

SUMMARY OF THE INVENTION

[0004] The present invention relates to a picket fence section which ismanufactured by a blow molding technique to produce a single componentof a substantial length defining a number of pickets and integral withhorizontal support members. These components are combined during theblow molding process and do not require any assembly of the pickets tothe horizontal members. The blow molding manufacturing approach can beused to produce a picket fence section of a length suitable for securingbetween two end posts.

[0005] Preferrably, the picket fence section has been modified toinclude pinch off areas in both the individual pickets and thehorizontal members to add strength to the final product.

[0006] A plastic picket fence section according to the present inventioncomprises an upper hollow horizontal member and a lower horizontalmember with both horizontal members extending the length of the fencesection and forming the major horizontal support structure. A pluralityof vertical extending picket members are spaced in the length of thehorizontal members and extend above and below the horizontal members.Each picket member is divided by the horizontal members into a topsection, middle section and a base section, with all of these sectionsbeing hollow. The top section extends above the upper horizontal memberwith the middle section extending between the two horizontal members andthe base section extending below the lower horizontal member. The middlesection of the picket fence connects and maintains the spacing betweenthe two horizontal members.

[0007] According to a preferred aspect of the invention, the picketfence section is greater than 30 inches in height and is of a lengthgreater than five feet.

[0008] According to a further aspect of the invention, the picket fencesection is greater than 30 inches in height and is of a length of abouteight feet.

[0009] According to yet a further aspect of the invention, the fencesection is symmetrical relative to a vertical plane passing through alength of the fence section.

[0010] In yet a further aspect of the invention, the fence section is ablow molded component.

[0011] According to yet a further aspect of the invention, eachhorizontal member includes at least one horizontal recess extending thelength of the horizontal member and this horizontal recess divides thehorizontal member internally into a series of horizontal hollowcavities.

[0012] In a different aspect of the invention, each horizontal extendingrecess is paired with a recess provided in the opposite side of thehorizontal member and the paired recesses divide the horizontal memberinto a series of horizontal extending hollow cavities.

[0013] In yet a further preferred aspect of the invention, eachhorizontal member is divided by paired recesses into an upper horizontalextending chamber, a centrally horizontal extending chamber, and a lowerhorizontal extending chamber.

[0014] In yet a further aspect of the invention, each picket is recessedon opposite sides of the picket to divide the hollow cavity of thepicket section into a series of hollow chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred embodiments of the invention are shown in the drawingswherein:

[0016]FIG. 1 an exploded partial perspective view showing a picket fenceincluding two end posts and a picket fence section;

[0017]FIG. 2 is a front view of a picket fence section;

[0018]FIG. 3 is a perspective view of a picket as it would have been hadit not been integrally molded with the horizontal members;

[0019]FIG. 3a is a sectional view taken along line A-A of FIG. 3;

[0020]FIG. 4 is a sectional view through one of the horizontal membersbetween pickets showing the various chambers thereof with one picketshown extending above;

[0021]FIG. 5 is a sectional view through a picket and through one of thehorizontal members showing the inner connection of the picket to thehorizontal members;

[0022]FIG. 6 is a partial front view showing the picket fence sectionadjacent a post for connection thereto;

[0023]FIG. 6A is a sectional view showing attachment of a horizontalmember to a connector;

[0024]FIG. 7 is a perspective view of a connector used to secure thepicket fence section to a post;

[0025]FIG. 8 is a front view of the connector of FIG. 7;

[0026]FIG. 9 is a partial perspective view of a blow molded post coverwith a pyramid cap integral therewith;

[0027]FIG. 10 is a blow molded post cover with a ball cap integraltherewith;

[0028]FIG. 11 is a blow molded post cover with integral flat cap; and

[0029]FIG. 12 is a cut through one of the post covers below the capshowing the wall section of a post cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The picket fence 2 shown in FIGS. 1 and 2 includes a picket fencesection 6 which is manufactured by blow molding and is a single piece.The picket fence section is supported at either ends by posts 4 andconnectors 8. The connectors 8 engage the horizontal members 22 of thepicket fence section and these connectors are mechanically fastened tothe post 4.

[0031] The posts 4 are preferrably made of wood and include an outercover 80 which encloses the wood post. This outer cover is alsopreferrably manufactured by blow molding and is a single integral pieceincluding the top cap of the post.

[0032] The picket fence section 6 as shown in FIG. 2 includes horizontalmembers 22 and a series of pickets 20. The pickets in this case are allof the same height, however, it is possible to have pickets of differentheights. The component shown in FIG. 2 is a single integral piecemanufactured by blow molding. Preferrably, the picket fence section 6 isapproximately eight feet long and preferrably of a height of about fourfeet or less. The height can vary depending upon the particularapplication and need not be consistent. For example, the pickets can beof different heights to form a scallop pattern between the ends of thesection. The most common heights are 36 and 42 inches, as well as thescallop or curved design. For warehousing and ease of distribution, thefence sections all stored on a four foot by eight foot skid. The size isalso easily transported and manageable by the consumer. The picket fencesections are also partially nestable by shifting the fence sections suchthat the horizontal rails are supported on the pickets 20. This addsstability to the stacked fence sections.

[0033] The individual pickets 20 and the horizontal members 22 arehollow and the horizontal members are reinforced by a series of recesses28. These recesses are referred to as pinch offs in blow molding andeach horizontal member has two horizontal pinch offs 28. These pinchoffs serve to stiffen the horizontal members which provide the primarysupport for the picket fence section. Each of the horizontal membersinclude end portions 50 with a small depressed area 52 which is used toform part of the connection with the connectors 8. The pickets 20 arereinforced by pinch offs 29.

[0034]FIG. 4 shows a cross section through one of the horizontal membersin the gap between pickets. As can be seen, the horizontal member 22 hasbeen divided into three hollow cavities, namely; the top chamber 40, themiddle chamber 42, and the bottom chamber 44. The pickets are generallyinterrupted by the horizontal members and are centered on thesehorizontal members. The picket fence section 6 is symmetrical to eitherside of the section. In this way, the appearance of the fence to theinstaller's side is the same as the appearance to the neighbour's side.

[0035] For the purpose of better understanding, a single picket, if notmanufactured as part of the fence section, is shown in FIG. 3. As can beseen, the picket has a U-shaped pinched off region 29 to add additionalstiffness. This pinched off region is not closed off at the base of thepicket as a horizontal pinch off at that point may tend to accumulatedirt. By tapering the recess out, any dirt which is washed down throughthe recess will pass out and over the bottom surface of the picket.

[0036]FIG. 3a shows a sectional view taken along line A-A of FIG. 3. Thepinch off regions 29 have basically defined a three chamber picket withtwo side chambers 32 and a central chamber 34. These chambers cooperateto provide a greater moment of inertia and stiffen the pickets. As canbe appreciated, the wall thickness is relatively thin and the stiffnessis achieved by the size of the chambers and the particular reinforcing.This is similar to the horizontal rails where the stiffness is increasedby the three spaced chambers.

[0037] In some cases it may be desirable to merely have horizontalmembers which generally are sized to correspond to a two-by-fournormally associated with a picket fence. In this case there can be asingle large chamber and the chamber can be sized to receive atwo-by-four through the fence section. This two-by-four can provideadditional reinforcing. This has not been found to be necessary for mostapplications as the stiffening provided by providing multiple chambersand pinch off regions does provide high strength.

[0038] This structural strength is somewhat surprising and there isconcern that the market will not immediately recognize this strength. Insome cases it may be more convenient to accept the markets misconceptionand provide them with a simple easily understood solution. This easilyunderstood solution would be the mere insertion of a two-by-four orother reinforcing member through the horizontal member or a chamberthereof. The multi-chamber horizontal members can be reinforced with aone inch by one inch metal or wood reinforcing member through the centerchamber.

[0039] The horizontal members at the various points where the picketsappear to pass through the horizontal members include stiffeningportions 56 which are aligned with the pinched offs 29 of each picket.These provide additional bracing between the top, middle, and bottomchambers of each horizontal member. This can be appreciated from thesectional view of FIG. 5 through a non pinch off region of one of thepickets. Basically the reinforcing 56 is achieved by not pinching offentirely between the top chamber 40, the middle chamber 42 and thebottom chamber 44.

[0040] This reinforcing only occurs at the pickets and the horizontalmembers will be fully pinched off as shown in FIG. 4 between thepickets. This also serves to provide a visual perception that thepickets are extending through the center of the horizontal members. Thefence section preferrably has at least 10 pickets approximately threeand one half inches wide. For eight foot nominal sections, there are 13pickets.

[0041]FIG. 6 shows the picket fence section 6 positioned adjacent thepost 4. A small gap is provided between the picket fence section and thepost. As can be appreciated, the picket fence is made of a plasticmaterial, preferrably high density polyethylene (HDPE), andaccommodation must be made for thermal expansion and contraction. Theconnectors 8 include a center port 62 which can slide on the end portionof the horizontal members 22. Each connector includes an outer flangearea 63 with securing slots 70 at a bottom edge of the flange andsecuring ports 72 on the top edge of the flange. The connector includesa projecting collar 64 to provide additional support for engaging theend portion 50 of a horizontal member 22. Support gussets 60 areprovided at the corners of the collar 64 and two additional end gussetsare provided along the center line of the connector. The connector ispreferrably made by injection molding.

[0042] To install a fence section, collars are inserted on thehorizontal members and the fence section is brought into place betweentwo posts positioned on eight foot centers. The posts are four-by-fourposts and include an outer sleeve as will be subsequently described.Once the fence section has been generally brought into position, it canbe appropriately lifted at either end thereof to position the fencesection at the appropriate height.

[0043] The connectors associated with the upper horizontal member can besecured to the post either by lifting the section into place andsupporting it on two screws which were previously located. The slots ofthe connectors are placed on these screws. These screws can beapproximately placed prior to bringing the section into place and thetop horizontal member can be hung in place, suspending the picket fencesection between the two posts. Once the fence section is generallypositioned, the installer can then fine tune the placement of the fencesection and accurately secure it by using screws through ports 72 of theconnector. Once the top connectors have been appropriately positioned,the screws in the slot openings 70 can be finally secured in place.

[0044] It has been found that it is not necessary to prehang theconnectors associated with the lower horizontal member. Thus to installa fence section, the installer would normally accurately locate twoscrews corresponding to each upper connector and effectively hang thefence section in place. Once so positioned, it can be finely tunedwithout any substantial difficulty. Once the connectors have beeninstalled on the posts, blind screw members can pass through theprojecting collar 60 to align with the depressions 52 of the horizontalmembers 71. These depressions 52 are not holes and the blind screws donot pierce the horizontal members. They merely engage the horizontalmembers as generally shown in FIG. 6a.

[0045] Additional details of the gusset supports the projecting collarand the base flange of the connectors are shown in FIG. 8. As can beseen from FIG. 8, the port 62 passes all the way through the connectorsuch that the connector can slide on past the end of the horizontalmember. The installer typically drills the holes 79 through which theblind screw members 71 engage the recess 52. This recess provides forexpansion and contraction, and also provides end stops.

[0046]FIGS. 9, 10, 11 and 14 show details of the post cover 80. The postcover 80 is again made by blow molding and is a single integral piece.In the case of FIG. 9, a pyramid cap 81 has been formed at one end ofthe post cover and the post cover is sized for sliding over thefour-by-four wooden post. In FIG. 10, a similar post cover is shown,however, it has a ball cap 83 as a decorative top piece. Again, thesecaps are integral with the cover. FIG. 11 shows a flat cap 85 variationwhich again is integral with the cover 80.

[0047]FIG. 12 is a sectional view through the post cover 80 below thedecorative top portion. The post cover includes a generally squarecenter section for sliding over the four-by-four post. It is sized toclosely correspond with the four-by-four post and as such, has sidesections approximately three and one half inches in length. The cornersof the post covers do include a projecting end segment 82 which allowsfor tolerance variations in the post dimensions and in any twisting ofthe post. Each of these corners provide a small amount of give to allowthe cover to slide over the four-by-four post. The post cover can beoversized in length and the bottom of the cover trimmed to theappropriate length.

[0048] The beads 82 also serve to center the connector 8 on the post.

[0049] Blow molding is a relatively old plastic molding process,however, it has been used for the manufacture of products such asgarbage cans. The manufacture of the picket fence section using blowmolding has eliminated a large portion of the manufacturing costsassociated with the mechanical fastening of extruded components as waspreviously done with respect to plastic sections. Surprisingly, thepicket fence section has considerable strength and has great advantageswith respect to ease of assembly, durability and low maintenancecharacteristics.

[0050] The blow molded post sleeves with integral top caps can encloseany wooden parts of the fence section and also provides a finishedsurface which is difficult to meet with respect to a wooden equivalent.

[0051] The blow molded picket fence section requires after blow molding,trimming of material between pickets and at the ends of the fencesection. This trimmed material can be recycled.

[0052] Although various preferred embodiments of the present inventionhave been described herein in detail, it will be appreciated by thoseskilled in the art, that variations may be made thereto withoutdeparting from the spirit of the invention or the scope of the appendedclaims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A plastic picket fencesection comprising an upper hollow horizontal member and a lowerhorizontal member with both horizontal members extending the length ofthe fence section and forming the major horizontal support structure, aplurality of vertically extending picket members space in the length ofsaid horizontal members and extending above and below said horizontalmembers, each picket member being divided into a top section, a middlesection and a base section with all of said sections being hollow, eachtop section extending above said upper horizontal and separated from therespective middle section by said upper horizontal member, each middlesection extending between and connecting said horizontal members withthe respective base sections extending below said lower horizontalmember and separated from the respective middle section by said lowerhorizontal member.
 2. A plastic picket fence section as claimed in claim1 wherein said section is greater than 30 inches in height and is of alength greater than five feet.
 3. A plastic picket fence section asclaimed in claim 1 wherein said section is greater than 30 inches inheight and is of a length of about eight feet.
 4. A plastic picket fencesection as claimed in claim 1 wherein said fence section is symmetricalrelative to a vertical plane through said fence section.
 5. A plasticpicket fence section as claimed in claim 1 wherein said section is asingle integrally molded component.
 6. A plastic picket fence section asclaimed in claim 5 wherein said fence section is a blow moldedcomponent.
 7. A plastic picket fence section as claimed in claim 5wherein each horizontal member includes at least one horizontal recessextending in the length of the horizontal member and dividing saidhorizontal member internally into a series of horizontally extendinghollow cavities.
 8. A plastic picket fence section as claimed in claim 7wherein each horizontal extending recess is paired with a recessprovided on the opposite side of the horizontal member and said pairedrecesses divide said horizontal member into said series of horizontallyextending hollow cavities.
 9. A plastic picket fence section as claimedin claim in claim 8 wherein each horizontal member is divided by saidpaired recesses into an upper horizontally extending chamber, a centralhorizontally extending chamber and a lower horizontally extendingchamber.
 10. A plastic picket fence section as claimed in claim 9wherein said central horizontally extending chamber is the largesthorizontally extending chamber.
 11. A plastic picket fence section asclaimed in claim 1 wherein each picket section is divided by opposedrecesses in each section which divide the hollow cavity of the picketsection into a series of hollow chambers.
 12. A plastic picket fencesection as claimed in claim 1 wherein each picket has opposed facesparallel to the length of the fence section and each face includes arecess inwardly positioned from each side of the picket and extendsaround the face of the picket on the sides and the top thereof.
 13. Aplastic picket fence section as claimed in claim 12 wherein said fencesection is defined by a host of generally closed hollow cavities whichare interconnected through pinch off regions.
 14. A plastic fencesection as claimed in claim 13 which is a blow molded component andrequires no additional horizontal reinforcing throughout its length forsupport between two opposed fence posts.
 15. A picket fence systemcomprising a series of vertical posts and a series of plastic picketfence sections with a picket fence section disposed between opposedposts such that the gap between two opposed posts is closed by one ofsaid plastic picket fence sections and each picket fence section issupported by and suspended between opposed said posts, and wherein eachpicket fence section comprises an upper hollow horizontal member and alower horizontal member with both horizontal members extending thelength of the fence section and forming the major horizontal supportstructure, a plurality of vertically extending picket members space inthe length of said horizontal members and extending above and below saidhorizontal members, each picket member being divided into a top section,a middle section and a base section with all of said sections beinghollow, each top section extending above said upper horizontal andseparated from the respective middle section by said upper horizontalmember, each middle section extending between and connecting saidhorizontal members with the respective base sections extending belowsaid lower horizontal member and separated from the respective middlesection by said lower horizontal member.
 16. A single piece blow moldedcombination post cap and post cover comprising an elongate body portionsized for enclosing a wooden or metal fence post with a post cap at oneend thereof closing one end of said post cover and integral therewith.17. A single piece blow molded combination post cap and post cover asclaimed in claim 16 wherein said post cover in section has a pluralityof wall sections joined at corners and at least some of said cornersproject outwardly and form expansion corners which can locally distartand increase the size of said post cover.
 18. A single piece blow moldedcombination post cap and post cover as claimed in claim 16 wherein saidpost cover is generally square in cross section with expansionprojections at each corner.